The invention relates to a sewing machine having a device for adjusting the horizontal movement or transportation distance of the feed dog by virtue of a rotatory stitch length regulator which has a continuous adjustment and includes an eccentric. The stitch length regulator is disposed on a rotating shaft and is connected to and drives the feed dog.
U.S. Pat. No. 2,643,625 discloses a sewing machine, in which a rotating shaft has an inner eccentric that is surrounded by an outer eccentric. The inner eccentric rotates with respect to the rotating shaft, whereas the outer eccentric rotates with the shaft. Although this arrangement renders it possible to change the degree of eccentricity of the outer eccentric in relation to the shaft axis, it is necessary when carrying out the adjustment to fixedly hold the inner eccentric while the shaft is rotated. Thus, adjustment is difficult, time consuming, requires special tools and is cumbersome.
For the foregoing reasons, there is a need for a sewing machine in which the stitch length can be adjusted by a simple manual adjustment using a common hand tool.